but in terms of the specific cause here, that's going have to be determined by a full investigation. >> so many passengers that ride those rails looking for reassurance. gio, back with us live now. and federal investigators still at the scene? >> reporter: that's right, david. you can see them down there right now, searching for clues. you can bet, they're going to be there all night long. by the way, david, overnight, cranes will be moving in to start clearing that wreckage. >> bringing in those large cranes. gio benitez leading us off. gio, thank you. neighbors describing the crunch, the screeching when that train went off the tracks. here's just some of what we heard today. >> it woke me up. i heard it from on the top of the hill. and i come down here, it's devastating. i just heard, like, a screeching noise, you know? like a subway car, like that. and then, within seconds, the ambulance and the fire trucks started coming past my window and i knew something big happened. >> a big boom. it woke me, so -- this is a bad curve. definitely.